Online teaching is an inseparable part of the education system and necessitates the development of educators' abilities to integrate knowledge on assessment and techno-pedagogic knowledge to enable the intelligent use of basic online assessment methods. This study considers how the cocreation of a teamwork rubric to assess the production of a learning unit designed by students in groups contributed to the online self-assessment of collaborative work processes from the perspective of student-teachers. Cocreation of a rubric was combined with graded self-assessments to stimulate students' increased responsibility for the learning process. I employed a mixed-methods methodology for the research, including both qualitative and quantitative data collection and analysis to investigate students' attitudes concerning the contribution of their cocreation of rubrics to the improvement of their assignments and their assessment skills. The sample included 120 student-teachers at the graduate level. The results clarify the contribution of cocreating rubrics to student-teachers' online assessment of collaborative work processes and reveal their attitudes concerning the use of collaborative processes in their teaching. Creating a positive learning experience for the student-teachers can train and encourage them to employ alternative assessment methods in their teaching.